THREE EXTINCT SPECIES OF ELEPHANT. 279 
have been unable to perceive any greater distinction than can be accounted for by dif- 
ference of age; but in the two specimens I am now about to refer to, and which appear 
as nearly as possible in the same stage of development, there is a difference in propor- 
tionate thickness which cannot be so accounted for. One of the two specimens is 
figured in Pl. LIL. figs. 42 and 42a; the other has not been figured. At first sight these 
two fragments might be supposed to be the right and left sides of the same sym- 
physis, each being about 2 inches long, and broken off, as would seem to be usual, at 
the part where the ramus is necessarily weakened by the presence of the alveolus of 
the 3rd milk-molar. Closer inspection, however, of the fragments shows that they do 
not correspond as the opposite portions of the same jaw would. 
The left fragment is thicker than the right, measuring at the smallest part behind the 
symphysis 0-5, and the other 0:4; and the distance between the mental foramen and 
the accessory foramen behind it (single in either case) is, in the left, 0-35, and, in the 
right, 0:45, though this is perhaps not a very important particular. ‘The symphysial 
facet in the left portion is 1" x 0""5, and in the left 1" 01. 
The general antero-posterior curve, including that of the diastemic edge, is more 
rounded in the left fragment. And in consequence of this difference, and from the 
greater incurvation also, as it were, of the diastemic border, the left fragment, when 
viewed from above, appears much more rounded on the outer face. 
The differences, in fact, between the two fragments are amply sufficient to show not 
only that they cannot have belonged to the same individual, but, in my opinion, to 
indicate an important and, perhaps, a specific distinction, when it is considered that 
the bones are both in the same stage of development. 
4. Bones of the Extremities. 
I have been unable to detect in the collection any bones belonging to the trunk of very 
young animals; but numerous specimens of various bones belonging to the fore and 
hinder extremities occur, amongst some of which, as it seems to me, significant indications 
of two distinct forms may be perceived. 
(1) Anterior Extremity. 
Of very young humeri we are in possession of three specimens, sufficiently entire to 
afford some diagnostic characters; two of these are figured in Pl. LIL. figs. 49 & 50. The 
former is the almost entire shaft of the left humerus; it is apparently slightly rolled at 
each end, and an angular fragment has been recently broken off obliquely at the upper 
end in front. No part of either epiphysial surface is left; but it is nevertheless clear 
that the specimen represents very nearly the entire length of the interepiphysial shaft. 
With due allowance for the great difference in age, the general characters of this speci- 
men correspond so closely with those of the humerus figured in Pl. XLIX. fig. 26, that 
little doubt can be entertained with respect to their belonging to the same species. One 
